"It won't burn half an hour," said he, surveying the pile. "And we ought to be able to keep it going all night. There's plenty of stuff in the valley, but we can't have him come down there, with the tower, the antennae, and all the rest of the mess." "We might--show him--the big Ray," ventured Atterbury. "The thing--can be pointed up--and I can--keep the turbine running. You can start--the fire--as soon as you--hear his motors--and I'll shut down--as soon as I see your fire." "Good idea!" agreed Bennie. "Only don't run continuously. Show the Ray for a minute every quarter of an hour, and on no account start up after you see the fire. If he thought the vertical beam was a searchlight and flew through it----" Bennie shuddered at the thought of Burke driving his aeroplane through the Ray that had shattered the Atlas Mountains. So it was arranged. Half an hour after sunset Atterbury shut himself up in the Ring, and while Bennie climbed the trail leading to his post on the plateau, he heard the creaking of the great inductor as it slowly turned on its trunions. It was pitch dark by the time he reached the pitifully small pile of brush which they had collected, and he poured some of the oil over it and sat down, drawing a blanket around his shoulders. He felt very much alone. Suppose the inductor failed to work? Suppose Atterbury turned the Ray on him? Suppose.... But his musings were shattered by a noise from the valley, a sound like that of escaping steam, and a moment later the Lavender Ray shot up toward the zenith. Bennie lay on his back and watched it, mindful of the night before the last when he had watched the Ray from the tower descending upon the cliff. He wondered if he should see any meteorites kindle in its path, but nothing appeared and the Ray died down, leaving everything in darkness again. Fifteen minutes passed and again the ghostly beam shot up into the night sky. Bennie looked at his watch. It was nearly half-past eight. The cold made him sleepy. He drew the blanket about him....